1. Technical Field
The present invention is generally directed to a filter assembly for use in a dust collector. In particular, the present invention is directed to a filter cartridge and structure for mounting and supporting the filter assembly in the dust collector.
2. Description of the Prior Art
Dust collectors, such as baghouses, for filtering particulate-laden air are well known. A typical baghouse has a housing with a clean air chamber and a dirty air chamber. The two chambers are separated by sheet metal, commonly referred to as a tubesheet. The tubesheet has a number of openings through which cylindrical filters, such as bags or cartridges, extend. The filters are suspended by the tubesheet and extend into the dirty air chamber. Particulate-laden air is introduced into the dirty air chamber. The air passes through the filters and through the openings in the tubesheet into the clean air chamber. The particulates collect on the exterior surfaces of the filters. The cleaned air is exhausted from the clean air chamber into the environment, or recirculated for other uses.
Important in the design of a filter bag or cartridge and its support structure is that a good seal exists between each filter and the tubesheet. If a good seal does not exist, particulate-laden air will leak around the filter, through the tubesheet opening and into the clean air chamber. This leakage results in contaminated air in the clean air chamber. The filters also require periodic replacement and it is important that the filters are easily removable and replaceable.
Numerous attempts have been made to develop a baghouse filter and supporting structure for attaching a filter element to a baghouse tubesheet. U.S. Pat. Nos. 4,292,057; 4,424,070; 4,436,536; 4,443,237 and 4,445,915 are representative examples of prior art filter elements and attachment structure. U.S. Pat. No. 5,632,791 discloses a flexible sleeve molded from relatively soft urethane material. U.S. Pat. No. 5,746,792 discloses a metallic end collar that is engagable with a flexible gasket for sealing against a tubesheet.
In spite of prior art attempts at solving the problems and disadvantages with prior art filters, the prior art filters and associated structure for attaching the filters to a baghouse tubesheet tend to be complex, which adds to the cost of the filter and installation in the baghouse. The prior art filters also have not been altogether satisfactory in preventing particulate-laden air from leaking from the dirty air chamber, through the tubesheet opening, and into the clean air chamber. The mounting and sealing of filters within a baghouse tubesheet remains one of the most time-consuming and expensive operations in the manufacture of baghouses and in the replacement of filters.
Prior art filters and their support structure also present problems when the filters require replacement. It is common for workers to walk on the upper surface of the tubesheet, and even on the top of the filter support structures, during periodic checking or replacement of the filters. It has been found that, walking on the tubesheet and filter support structures often causes the sealing structure to deform or contort, thus breaking its seal with the tubesheet and resulting leaks between the dirty air and clean air chambers of the baghouse.
Prior art filters with metal support structure can be expensive to manufacture. The metal support structure can also take a relatively long time to fabricate. Accordingly, the need exists for a filter and supporting structure which is inexpensive to quickly manufacture, easy to install and replace in a baghouse and that maintains a good seal. The present invention fills these and other needs, and overcomes the drawbacks of the prior art.